yooper_fisher
6/7/2011 10:25:00 AMI have also seen this parasite on fish in Lake Walker. I'm curious to find out about it also
Sculpin
6/7/2011 11:41:00 AMCould be furunculosis (bacterial infection) or something parasitic like "white spot" disease. Both are common problems in rainbow trout aquaculture. Fish found with such dieases in hatcheries are typically treated with antibiotics (for bacterial infections) or formalin baths (for parasites). I have put in a request to the WDFW stocking group for any info. they might have on fish health issues at the Puyallup Hatchery where these fish originated. I'll post their response, if I get one. Don't hold your breath.
chengpu
6/7/2011 12:55:00 PMThanks Sculpin! I am really curious as to what is on these fish. Whats odd is that i fish Wilderness alot. Every fish i caught in May was clean. It wasnt until this past week that this infection showed up. Its gonna put a dent in my smoked trout supply.
Sculpin
6/8/2011 9:53:00 AMOkay. chenpu and yooper_fisher, I heard back from WDFW this morning regarding the parasite lesions you are wseeing on fish in Wilderness and Walker lakes. WDFW response follows:
"This sounds like a copepod. The “blister” is the actual copepod and the “worm-like protrusion” is the egg sac. There are a number of species of copepods that are commonly found in both fresh and saltwater. We do not see salmonicola at Puyallup Hatchery, but fish will become infested after planting in the lake. The copepod does not have a big impact on the fish, unless the gills are heavily infested, but it’s site of attachment can become infected with fungus or bacteria.
Humans cannot become infected with this parasite and the fish are suitable for human consumption unless the parasite load is heavy causing deterioration of the flesh by secondary infection."
I assume that it takes a while for the copepod to find a host fish and start this portion of its lifecycle. Perhaps, the timing of their attachment to the host for egg laying is dependent on water temperature. All for now, tight lines!
Sculpin
"This sounds like a copepod. The “blister” is the actual copepod and the “worm-like protrusion” is the egg sac. There are a number of species of copepods that are commonly found in both fresh and saltwater. We do not see salmonicola at Puyallup Hatchery, but fish will become infested after planting in the lake. The copepod does not have a big impact on the fish, unless the gills are heavily infested, but it’s site of attachment can become infected with fungus or bacteria.
Humans cannot become infected with this parasite and the fish are suitable for human consumption unless the parasite load is heavy causing deterioration of the flesh by secondary infection."
I assume that it takes a while for the copepod to find a host fish and start this portion of its lifecycle. Perhaps, the timing of their attachment to the host for egg laying is dependent on water temperature. All for now, tight lines!
Sculpin
yooper_fisher
6/8/2011 3:10:00 PMThank you so much Sculpin! Chengpu, I too don't see a heavy infestation of this at Walker until late june into july and it tends to be more on the smaller fish. I have seen it really take over on the gills too. I have eaten these fish and have had no problems yet.